I have noticed though that with e-tickets (as long as you have a seat assignment and/or upgrade ahead of time) the process is extermely fast. I checked into an international flight (where AA has in my profile my Passport # etc...) in under 3 minutes (including checking a bag)-- I was amazed.

(Of course it is a different story entirely if you have your tickets, need to process an upgrade for which you have a seat assignment but you are redeeming a certificate that is already in your possession but that has not been entered into the computer. In that case, bring a book -- you will be there for a while!)